Add Points to a Plot

Usage

# S3 method for class 'spherical'
text(x, labels = seq_along(x[, 1]), upper.hem = FALSE, earea = TRUE, ...)

x: object of class "Vec3", "Line", "Ray", "Plane", "Pair", or "Fault", where the rows are the observations and the columns are the coordinates.
labels: a character vector or expression specifying the text to be written. An attempt is made to coerce other language objects (names and calls) to expressions, and vectors and other classed objects to character vectors by as.character. If labels is longer than x and y, the coordinates are recycled to the length of labels.
upper.hem: logical. Whether the projection is shown for upper hemisphere (TRUE) or lower hemisphere (FALSE, the default).
earea: logical TRUE for Lambert equal-area projection (also "Schmidt net"; the default), or FALSE for meridional stereographic projection (also "Wulff net" or "Stereonet").
...: arguments passed to graphics::text()

stereoplot()
points(Line(c(90, 80), c(10, 75)), col = 1:2)
text(Line(c(90, 80), c(10, 75)), labels = c("L1", "L2"), col = 1:2, pos = 3)